Draft equalizer



June 28, 1960 H. F. JUMPER, JR 2,942,688

7 DRAFT EQUALIZER Filed Sept. 20, 1957 2 Sheets-Sheet 1 Henry F. Jumper. J:

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W EMLW June 1960 H. F. JUMPER, JR ,9

DRAFT EQUALIZER Filed Sept. 20, 1957 2 Sheets-Sheet 2 20 Fig.2 4 /2 Henry E Jumper. Jr INVENTOR.

United States Patent Q DRAFT EQUALIZER Henry F. Jumper, Jr., Ashley Automatic Wood Stove Company, Inc, Columbia, S.C.

Filed Sept. 20, 1957, Ser. No. 685,116

2 Claims. (Cl. 183-6) The present invention generally relates to an attach ment for a stove and more particularly a device for insertion in the exhaust pipe or in the exhaust system for the combustion products for introducing atmospheric air into the combustion products as they are exhausted for diluting the same thereby reducing the formation of creosote and similar tars and for also providing secondary combustion supporting air in the form of secondary air for furnishing oxygen for the burning of incompletely burnt gases before they get into the chimney.

An object of the present invention is to provide an attachment in the form of a draft equalizer which may conveniently be constructed in the form of a section of stove pipe incorporating structural means for providing the inlet of atmospheric air into the reduced pressure area of the exhaust stack thus equalizing the pressures, diluting the exhaust products and also supplying secondary air for more complete combustion of the incompletely burnt gases which normally are discharged to the atmosphere.

Another object of the present invention is to provide a draft equalizer which will aid in the prevention of back drafts down the chimney or'aid in reducing the severity of such back drafts.

A' further important object of the present invention is to' provide a draft equalizer which is simple in construction, easy to install, adapted for use in various types of stoves and relatively inexpensive to manufacture;

These together with other objects 'andadvantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being bad to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and'inwhich:

Figure 1 is a perspective view of the draft equalizer of the present invention showing one mode of installation thereof;

Figure 2 is a longitudinal, vertical sectional view taken substantially upon a plane passing along a longitudinal centerline of the draft equalizer;

Figure 3 is a longitudinal, sectional view taken substantially upon a plane passing along section line 33 of Figure 2 illustrating further structural relationships of the draft equalizer;

Figure 4 is a tranverse, vertical sectional view taken substantially upon a plane passing along section line 4-4 of Figure 2 illustrating the structure of one set of air inlets; and

Figure 5 is an exploded group perspective view showing schematically the arrangement of the air inlets and the tubular member through which they are inserted.

Referring now specifically to the drawings, the numeral generally designates the draft equalizer of the present invention which may be conveniently in the form of a section of stove pipe which is cylindrical in construction and designated by the numeral 12. This section of stove pipe 12 may have the usual crimped end 14 for insertion into a flanged opening 16 in the casing 18 of the stove ice and may in turn receive the crimped end 20of a second section ofstove pipe 22. The particular length of the cylindrical stove pipe section 12 may be altered as desired and the device may be altered for fitting various sizes of stovepipes and may be inserted in an adapter rigidly connected to the casing or installed in any other manner in the exhaust system of the stove which is'generally designated by the numeral 24.

Disposed concentrically within the cylindrical stove pipe section 12 is a longitudinally extending tubular member 26 of considerably less cross-sectional area than the stove pipe section 12. The tubular member 26 extends beyond the crimped end 14 for projecting into the interior of the stove 24 for a purpose described hereinafter. The other end of the tubular member 26 terminates generally in alignment with the other end of the stove pipe section 12;

The elongated tubular member 26 is provided with apair of diametrically opposed and aligned openings 28 for receiving. a transverse pipe member 30 therethrough. The transverse pipe member 30 extends diametrically of the cylindrical stovepipe section 12 and extends through the cylindrical stovepipe section 12 and terminates flush therewith thus communicating the interior of the transverse pipe 39 with the atmosphere. One side surface of the transverse pipe 3 9 is provided with an elongated ovalshaped opening 32 disposed centrally therein which faces the end of the tubular member 26 disposed remotely from the crimped end 24 of the stove pipe section 12. Figure 4 clearly shows the arrangement'of the oval shaped opening 32 in the pipe 3ll'thus communicating the tubular member 26 with the atmosphere inasmuch as the transverse tubular member 30 is communicated with the atmosphere. member 26 remote from the crimped end 14 of the stove pipe section 12.

Disposed immediately inwardly of the transverse pipe 30 is a closure disk 34 which may be permanently secured within the tubular member 26 such as by welding or the like. Immediately inwardly of the circular disk 34, the tubular member 26 is provided with a pair of diametrically opposed and aligned openings or apertures 36 which are arranged in staggered relation to the openings 28. The aligned openings 36 receive a transverse tubular member 38 substantially identical'in construction with the tubular member 3 and'which is provided with an oval shaped opening 4% in the side surface thereof which faces the end of the tubular member 26 disposed adjacent the crimped end 14 of the cylindrical stove pipe section 12.

As clearly shown in Figure 5, if the transverse member' 39 is disposed in horizontal relation, then the transverse member 33 is disposed in vertical relation. The transverse member 33 also extends through and terminates flush with the cylindrical pipe section 12 thus communicating the tubular member 26 with the atmosphere inwardly of the closure disk 34 thus communicating both ends of the tubular member 26 with the atmosphere but maintaining the tranverse member 38 isolated from the transverse member 30. Thus, any air entering the transverse member 38 must necessarily proceed inwardly of the stove 24 to be discharged from the inner end of the tubular member 26. Conversely, any air entering the tubular member 30 will be discharged from the tubular member 26 into the stove pipe section 12 remote from the stove 24 and adjacent the stove pipe section 22. The transverse members 30 and 38 as well as the disk 3 may be mounted in permanent relationship by any suitable means such as Welding or the like. The entire structure may be constructed of similar material to that employed in stove pipe construction such as sheet metal which may be corrosive resistant or of any suitable material.

The opening 32 faces the end of the tubulareffects to the stove.

stove and if there is no combustion air supplied for them In accomplishing oneof the objects of the invention, the vacuum created by the draft of the exhaust products being discharged through the chimney to the atmosphere will cause atmospheric air to be drawn in through the transverse tubular member 30 into the tubular member 26 and discharged into the. exhaust products. The discharge 7 of this'atmospheric air into the. exhaust products will cause a dilution of the exhaust products which will substantially reduce or eliminate creosote formation due to the condensation of creosote forming tars in the exhaust products. In accomplishing another object, air will be drawn inthrough the. transverse tubular member 38 by the draft of the exhausting products and the reduction in pressure created thereby and will be discharged as secondary air into the stove 24 due.to the orientation of the inner end of the tubular member 26 in the stove 24 as shown in Figures 2 and 3. 'This secondary air furnishes oxygen for the more complete burning of' combustion gases before such gases can 'get into thechimney. The elimination of these unburnt gases also acts as a double check for the elimination of creosote due to the further elimination of such creosote forming tars. If any of these gases do get into the chimney unburned, then the dilution air entering through the transverse tubular member 30 will effectively dilute these to prevent condensation. two tubes or transverse members 30 and 38 furnish dilution air and also serve as an outlet to eliminate-back draft because when a back draft occurs down the chimney, the two dilution tubes eliminate the pressure or the severity of theback draftand allow some of the air from the back'draft to be released through the two dilution tubes thus keeping it from the stove and keeping it from blowing out the flame or otherwise causing detrimental *In wood burning stovesfit quiteoften occurs that the" fire'is in a smoldering state with no actual flame. When this occurs, combustible gases tend to vaporize or actual: ly boil out of the wood and they rise to the top of the 'to'burn they accumulate; If combustion air issuddenly furnished, they explode; This slight explosion causes the stove to putt out smoke and this smoking usually occurs 'when'the flame is kindled back after it has been in a opens smoldering state or the thermostatic control damper opens when the stove cools down and combustion air is suddenly supplied. When the damper opens. either by a flICImOStEIfiC'COHiI'OI or by hand, if an accumulation of these gases is present in the stove they'will' cause a slight explosion. .The secondaryair for combustion furnished by the draft equalizer of the present invention will support combustion of these gases as they rise from the wood and will not allow them to accumulate. Of course,

some of these gases will rise and go into the chimney without any explosion these gases may be condensed and form creosote. g

" In actual tests, {the present invention has reduced the severity of back drafts which have been mechanically produced in a chimney and the tubes permitted suflicient of the downward movement of air to be exhausted to eliminate detrimental effects on the flame. By mechanically producinga suflicient back draft to'physically blow the flame out, the flame would kindle back smoothly each time the back draft was stopped. The reason for the 6 the draft equalizer of the present inventionare as fol lows: V

Y (1) The draft equalizer is serving the purpose of eliminating creosote going into the flue, this is done by the air that is bled in throughtube or. transverse pipe '30-] It is also emphasized that the the stove and have a relatively high condensing tempera- Y ture. The air bled in dilutes the exhaust products. This has the eifect of lowering the condensing temperature. When condensing'temperatu're is being lowered, the products have a better chance of getting out of the chimney without any creosote condensing out. The amount of creosote removed will be dependent upon various factors including the types of wood and operating temperatures.

(2) The draft equalizer is furnishing secondary air for combustion and by furnishing this secondary air the draft equalizer helps eliminate small gas explosions that causes pufiing. It also improves the performance of the stove by causing the flame to rekindle smoothly.

(3) The draft equalizer helps make backdraft milder by bleeding out part of the pressures as they come down through the flue. It also bleeds part of the pressures out of the stove that are caused by the backdraft out through transverse tubular member 38( If the damper is closed and the backdraft is severe enough to blow the flame out, the draft equalizer will furnish secondary air for combustion immediately after the backdraft.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction 'and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

. What is claimed as new is as follows:

1. A draft equalizer for a stove comprisinga cylindrical pipe section adapted to be inserted into an exhaust line, between the stove and chimney, a concentric tubular member disposed in said cylindrical pipe section and being of considerably lesser cross-sectional area, a closure member extending completelyacross the cross-sectional area of thertubular member'and dividing said concentric tubular member'into two separate open'ended portions sealed in relation to each other by'said closure member, a transverse tubular member extending through each open ended portionof the concentric tubular'member with each transverse member' extending through the pipe section and communicated with the atmosphere, each of said transverse members having a central opening communicating the transverse member with the concentric tubnlarmefnher, said transverse tubular member disposed inwardly of the closure member in the concentric tubular member admitting secondary air into the stove for supporting combustion ofunburned gases with the transverse tubular member disposed outwardly of the closure member in the concentric tubular member admitting air for dilution of exhaust gases thus reducing the condensation temperature thereof whereby the exhaust gases may be exhausted to the atmosphere before they reach the lowered condensing temperature said transverse tubular members being of equal size with the central openings being oval-shaped and facing the open ends of the portions of the concentric tubular member formed by'the closure member.

2. A draft equalizer for a stovecomprising a tubular exhaust section disposed between the combustion chamber of the stove and chimney, a longitudinal tubular member disposed in said exhaust section and being coaxial therewith and of considerably lesser cross-sectional area, a rigid, imperforate closure member extending completely across the cross-sectional area of said longitudinal tubular member and dividing said longitudinal tubular member into two separate open ended portions sealed in relation to each other by said closure member, a radially extending tubular member extending radially into each portion of the longitudinal tubular member with each radially extending tubular member extending through the. exhaust section and communicating with the atmosphere, each of said radially extending tubular members having an open 5 6 inner end communicating the longitudinal tubular memhausted to the atmosphere before they reach the lowered her with the atmosphere, said radially extending tubular condensing temperature. member disposed inwardly of the closure member in the longitudinal tubular member admitting secondary air into References cued m the file of thls Patent the combustion chamber of the stove for supporting com- 5 UNITED STATES PATENTS bustion of unburned gases with the radially extending tubular member disposed outwardly of the closure member 646863 M fNaughton et 1900 in the longitudinal tubular member admitting air for dilu- 1284053 Bnggs 1918 tion of exhaust gases thus reducing the condensation tem- 1824820 Hynes Sept 1931 perature thereof whereby the exhaust gases may be ex- 10 2038567 Imm- 1936 

